The diastereoisomers methyl 5‐(S)‐[2‐(R)/(S)‐methoxycarbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methylphenyl)‐4,5‐dihydropyrazole‐3‐carboxylate

The title diastereoisomers, methyl 5‐(S)‐[2‐(S)‐methoxy­carbonyl)‐2,3,4,5‐tetra­hydro­pyrrol‐1‐yl­carbonyl]‐1‐(4‐methyl­phenyl)‐4,5‐di­hydro­pyrazole‐3‐carboxyl­ate and methyl 5‐(S)‐[2‐(R)‐methoxycarbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methyl­phenyl)‐4,5‐di­hydro­pyrazole‐3‐carboxylate, both C₁₉H₂₃N₃O₅, have been studied in two crystalline forms. The first form, methyl 5‐(S)‐[2‐(S)‐methoxy­carbonyl)‐2,3,4,5‐tetrahydropyrrol‐1‐ylcarbonyl]‐1‐(4‐methylphenyl)‐4,5‐di­hydro­pyrazole‐3‐carboxyl­ate–methyl 5‐(S)‐[2‐(R)‐methoxy­carbonyl)‐2,3,4,5‐tetra­hydro­pyrrol‐1‐yl­carbonyl]‐1‐(4‐methylphenyl)‐4,5‐dihydropyrazole‐3‐carboxylate (1/1), 2(S),5(S)‐C₁₉H₂₃N₃O₅·2(R),5(S)‐C₁₉H₂₃N₃O₅, contains both S,S and S,R isomers, while the second, methyl 5‐(S)‐[2‐(S)‐methoxycarbonyl)‐2,3,4,5‐tetrahydro­pyrrol‐1‐ylcarbonyl]‐1‐(4‐methyl­phenyl)‐4,5‐di­hydro­pyrazole‐3‐carboxyl­ate, 2(S),5(S)‐C₁₉H₂₃N₃O₅, is the pure S,S isomer. The S,S isomers in the two structures show very similar geometries, the maximum difference being about 15° on one torsion angle. The differences between the S,S and S,R isomers, apart from those due to the inversion of one chiral centre, are more remarkable, and are partially due to a possible rotational disorder of the 2‐­(methoxycarbonyl)tetrahydropyrrole group.     

Cis‐ and trans‐bis(2‐cyano­ethyl­sulfan­yl)(decane‐1,10‐diyldithio)tetra­thia­fulvalene

The isomeric title compounds, 2,7‐bis(2‐cyanoethylsulfanyl)‐3,6‐(decane‐1,10‐diyldithio)tetrathiafulvalene and 2,6‐bis­(2‐cyanoethylsulfanyl)‐3,7‐(decane‐1,10‐diyldithio)­tetra­thiafulvalene, both C₂₂H₂₈N₂S₈, comprise bis­(2‐cyano­ethyl­sulfan­yl)tetra­thia­fulvalene units tethered by a saturated deca­methyl­enedithio linker attached in either a cis or a trans manner. The tetra­thia­fulvalene (TTF) group is planar in the cis isomer, but distorted significantly from planarity and twisted about its long axis in the trans isomer. In both structures, inter­molecular inter­actions are segregated into regions in which TTF units are brought into close contact and regions where the polymethyl­ene chains are brought into close contact. In the cis isomer, TTF units exhibit π–π stacking inter­actions, while in the trans isomer they do not.     

The one‐electron oxidation product of a metallocenyl‐terminated cyanine

The 1‐(2,3,4,5,1′,2′,3′,4′‐octa­methyl­ferrocen‐1‐yl)‐3‐(ruth­eno­cen­yl)­allylium cation readily undergoes one‐electron oxidation to a dication in which an octa­methyl­ferrocenium moiety is bridged by a vinyl­ene group to a [(η⁶‐fulvene)(η⁵‐cyclo­penta­dienyl)­ruthenium]⁺ moiety. In the title compound, 1‐(2,3,4,5,1′,2′,3′,4′‐octa­methyl­ferrocen‐1‐yl)‐3‐(ruth­eno­cen­ylidene)prop‐1‐enium(2+) bis­(tetra­fluoro­borate), [Fe­Ru­(C₅H₅)(C₉H₁₃)(C₁₇H₁₉)]­(BF₄)₂, the C—C bond lengths in the bridge (average for two independent mol­ecules) are, starting from the ipso octa­methyl­ferrocenium carbon and ending at the exo carbon of the coordinated fulvene, 1.455 (6), 1.344 (3) and 1.449 (8) Å, indicating a localized electronic structure.     

Two biologically active thio­phene‐3‐carbox­amide derivatives

The compounds 2‐{[(E)‐(4‐methoxy­phenyl)­methyl­ene]­amino}‐N‐(3‐methyl­phenyl)‐4,5,6,7‐tetra­hydro‐1‐benzo­thio­ph­ene‐3‐carbox­amide, C₂₄H₂₄N₂O₂S, (I), and N‐(4‐meth­yl­phenyl)‐2‐{[(E)‐(4‐methyl­phenyl)­methyl­ene]­amino}‐4,5,6,7‐tetra­hydro‐1‐benzo­thio­phene‐3‐carbox­amide, C₂₄H₂₄N₂OS, (II), show antibacterial and antifungal activities. The m‐toluidine ring in (I) and the p‐toluidine ring in (II) are coplanar with their respective thio­phene rings. In (I), an intermolecular C—H⋯O hydrogen bond is present, whereas (II) does not exhibit any significant intermolecular interactions. However, in both compounds, an intramolecular N—H⋯N hydrogen bond forms a pseudo‐six‐membered ring, thus locking the molecular conformation and eliminating conformational flexibility.     

A dimeric constrained‐geometry titanium complex linked by double Ti–CH2–Al–CH2 heterocycles

In the structure of bis({N‐[di­methyl(1η⁵‐2,3,4,6‐tetra­methyl­in­den­yl)­silyl]­cyclo­hexyl­amido‐1κN}(methyl‐3κC)‐di‐μ₃‐methyl­ene‐1:2:3κ³C;1:3:3′κ³C‐tris(pentafluorophenyl‐2κC)titanium) benzene disolvate, [Me₂Si(η⁵‐2,3,4,6‐Me₄C₉H₂)(C₆H₁₁N)]Ti[(μ₃‐CH₂)Al(C₆F₅)₃][AlMe(μ₃‐CH₂)]₂ or [Ti₂(C₂₁H₇AlF₁₅)₂(C₂₁H₃₁NSi)₂]·2C₆D₆, the dimer is located on an inversion center, and the two Ti centers are linked by double Ti(μ₃‐CH₂)Al(C₆F₅)₃AlMe(μ₃‐CH₂) heterocycles. The electron‐deficient Ti centers are further stabilized by two α‐agostic interactions between Ti and one H atom of each bridging methyl­ene group.     

Intermolecular stacking in pyrazolo[3,4‐d]pyrimidine‐based pentamethylene‐linked flexible ­molecules

The crystal structures of 1‐{5‐[4,6‐bis­(methyl­sulfanyl)‐2H‐py­razolo­[3,4‐d]­pyrimidin‐2‐yl]­pentyl}‐6‐methyl­sulfanyl‐4‐(pyr­rolidin‐1‐yl)‐1H‐pyrazolo­[3,4‐d]­pyrimidine, C₂₂H₂₉N₉S₃, and 6‐methyl­sulfanyl‐1‐{5‐[6‐methyl­sulfanyl‐4‐(pyrrolidin‐1‐yl)‐2H‐pyrazolo­[3,4‐d]­pyrimidin‐2‐yl]­pentyl}‐4‐(pyrrolidin‐1‐yl)‐1H‐pyrazolo­[3,4‐d]­pyrimidine, C₂₅H₃₄N₁₀S₂, which differ in having either a pyrrolidine substituent or a methylsulfanyl group, show intermolecular stacking due to aromatic π–π interactions between the pyrazolo­[3,4‐d]­pyrimidine rings.     

Simvastatin

Simvastatin, or (1S,3R,7S,8S,8aR)‐8‐{2‐[(2R,4R)‐4‐hydroxy‐6‐oxo‐3,4,5,6‐tetra­hydro‐2H‐pyran‐2‐yl]­ethyl}‐3,7‐di­methyl‐1,2,3,7,8,8a‐hexa­hydro­naphthalen‐1‐yl 2,2‐di­methyl­butan­oate, C₂₅H₃₈O₅, is almost isostructural with lovastatin, and the general conformational features are closely related to those of other reported crystal structures of statins. The only hydrogen bond present facilitates the formation of infinite chains of mol­ecules along the b axis.     

Tetracycline hydrochloride: a synchrotron microcrystal study

The title compound, [(4S,4aS,5aS,6S,12aS)‐2‐amino­hydroxy­methyl­ene‐1,2,3,4,4a,5,5a,6,11,12a‐deca­hydro‐6,10,12,12a‐tetra­­hydroxy‐6‐methyl‐1,3,11‐trioxo­naphthacen‐4‐yl]­di­methyl­amm­onium chloride, C₂₂H₂₅N₂O₈⁺·Cl^?, a well known antibiotic, has been structurally characterized from an individual coarse powder grain by use of high‐intensity synchrotron radiation, in conjunction with an exercise in ab initio powder diffraction structure solution. Free refinement of all H atoms establishes the major tautomeric form of the protonated tetracycline mol­ecule without prejudice. The mol­ecule has extensive intramolecular hydrogen bonding involving most of the potential donors and acceptors, and all intermolecular hydrogen bonding uses the chloride anion as acceptor.     

A di­deoxy­dide­hydro­nucleoside derivative

We have synthesized a di­deoxy­dide­hydro­nucleoside derivative, 2(S)‐acetoxymethyl‐4‐[4‐amino‐2‐oxopyrimidin‐1(2H)‐yl]‐2,5‐di­hydro­furan, C₁₁H₁₃N₃O₄, which is an analogue of the potently anti‐HIV active compound, di­deoxy‐dide­hydro­cytidine (d4C). The target compound crystallizes with two mol­ecules in the asymmetric unit that differ primarily in the orientation of the C6′‐acetyl group. One mol­ecule has an extended conformation and the orientation of the acetyl group in the second mol­ecule gives an unusual hooked‐shaped conformation. The two conformers form A–B dimers via N—H?N hydrogen bonds. The dimers link via N—H?O hydrogen bonds to form chains parallel to the b cell axis.     

The conversion of a pyrrole trimer derivative into a 4,5,6,7‐tetra­hydro‐4‐­(pyrrol‐2‐yl)indol‐7‐yl­tosyl­aminoindole

Vilsmeier formyl­ation of trans‐1‐(4‐methyl­phenyl­sulfonyl)‐2,5‐bis(pyrrol‐2‐yl)­pyrrolidine leads to cleavage of the central ring then a reclosure resulting in the formation of trans‐N‐[2‐formyl‐4‐(5‐formyl­pyrrol‐2‐yl)‐4,5,6,7‐tetra­hydro­indol‐7‐yl]­toluene­sulfon­amide, C₂₁H₂₁N₃O₄S.     

Thia­mine tetra­phenyl­borate monohydrate: a two‐dimensional hydrogen‐bonded network with (4,4)‐topology

The title compound, 3‐[(4‐amino‐2‐methyl­pyrimidin‐5‐yl)­meth­yl]‐5‐(2‐hydroxy­eth­yl)‐4‐methyl­thia­zolium tetra­phenyl­borate monohydrate, C₁₂H₁₇N₄OS⁺·C₂₄H₂₀B⁻·H₂O, is a salt in which the thiamine cations are linked by hydrogen bonds into a two‐dimensional network having (4,4)‐topology. The stacked sheets form channels, which are occupied by the anions; the cations and anions are linked by C—H⋯π(arene) hydrogen bonds.     

Four bis(1‐chloro‐2,2,4,4‐tetramethyl‐3‐oxocyclobutan‐1‐yl)oligosulfanes

The four oligosulfanes, bis(1‐chloro‐2,2,4,4‐tetra­methyl‐3‐oxo­cyclo­butan‐1‐yl)­disulfane, C₁₆H₂₄Cl₂O₂S₂, (III), 1,3‐bis(1‐chloro‐2,2,4,4‐tetra­methyl‐3‐oxo­cyclo­butan‐1‐yl)­trisulfane, C₁₆H₂₄Cl₂O₂S₃, (V), 1,4‐bis(1‐chloro‐2,2,4,4‐tetra­methyl‐3‐oxo­cyclo­butan‐1‐yl)­tetrasulfane, C₁₆H₂₄Cl₂O₂S₄, (VII), and 1,6‐bis(1‐chloro‐2,2,4,4‐tetra­methyl‐3‐oxo­cyclo­butan‐1‐yl)­hexasul­fane, C₁₆H₂₄Cl₂O₂S₆, (VIII), all have similar geometric parameters, with the C—C bond lengths involving the chloro‐substituted cyclo­butanyl C atom being elongated to about 1.59 Å. There are two mol­ecules in the asymmetric units of the tri‐ and tetrasulfanes, and the mol­ecules in the latter compound have local C₂ symmetry. The mol­ecule of the hexasulfane has crystallographic C₂ symmetry. Most of the cyclo­butanyl rings are not perfectly planar and have slight but varying degrees of distortion towards a flattened tetrahedron. The polysulfane chain in each structure has a helical conformation, with each additional S atom in the chain adding approximately one quarter of a turn to the helix.     

Tetrabromo(2‐methylpyridine‐N)titanate(IV)

The reaction of 2‐methyl­pyridine with TiBr₄ affords tetra­bromo(2‐methyl­pyridine‐N)­titanate(IV), C₆H₇Br₄NTi. The environment around the Ti atom can be described as a slightly distorted trigonal bipyramid, with the nitro­gen base occupying an equatorial position. The crystal structure of the title compound is isomorphous with tetra­chloro(2‐methyl­pyridine‐N)­titanate(IV).     

Disappearance of intramolecular stacking due to one‐atom movement or increment of a `propyl­ene linker' in pyrazolo­[3,4‐d]­pyrimidine‐based ­flexible models

In the crystal structures of 4,6‐di­methyl­thio‐1‐[3‐(4,6‐di­methyl­thio‐2H‐pyra­zolo­[3,4‐d]­py­rimi­din‐2‐yl)­propyl]‐1H‐py­ra­­zolo­[3,4‐d]­py­rimi­dine, C₁₇H₂₀N₈S₄, and 1‐[4‐(4‐meth­oxy‐6‐methyl­thio‐1H‐pyra­zolo­[3,4‐d]py­rimi­din‐1‐yl)­butyl]‐5‐meth­yl‐6‐methyl­thio‐4,5‐di­hydro‐1H‐pyra­zolo­[3,4‐d]py­rimi­din‐4‐one, C₁₈H₂₂N₈O₂S₂, only intermolecular stacking due to aromatic π–π interactions between pyrazolo­[3,4‐d]­pyrimidinerings is present.     

Retroracemization using new forms of Belokon's original ligand: ­intermediate NiII complexes of N‐({2‐[N‐(S)‐alkylprolylamino]phenyl}phenylmethylene)‐(S)‐phenylalanine (alkyl is 2‐picolyl, 3‐picolyl or ethyl)

In the title compounds, [N‐(phenyl{2‐[N‐(S)‐(2‐picolyl)­prolyl­amino]­phenyl}methyl­ene)‐(S)‐phenyl­alaninato]­nickel(II), [Ni(C₃₃H₃₀N₄O₃)], (I), [N‐(phenyl{2‐[N‐(S)‐(3‐picolyl)­prolyl­amino]­phenyl}methyl­ene)‐(S)‐phenyl­alaninato]­nickel(II) hemihydrate, [Ni(C₃₃H₃₀N₄O₃)]·0.5H₂O, (II), and [N‐({2‐[N‐(S)‐ethyl­prolyl­amino]­phenyl}phenyl­methyl­ene)‐(S)‐phenyl­ala­nin­ato]­nickel(II), [Ni(C₂₉H₂₉N₃O₃)], (III), the Ni^II centres have approximate square‐planar coordination geometries from N₃O donor sets. The picolyl N atoms in (I) and (II) are too remote from the metal centres to interact significantly, but the metal coordination geometries experience tetrahedral distortion and/or displacement of the metal centre from the N₃O plane. These are linked to conformational differences between the ligands of the symmetry‐independent complexes (Z′ = 2), which in turn are related to molecular packing. In (III), where a less sterically demanding ethyl group replaces the picolyl substituents, there are none of the distortions or displacements seen in (I) and (II).     

2‐(6‐Bromo­pyridin‐2‐yl)‐6‐methyl‐[1,3,6,2]­diox­aza­borocane,a new stable (pyridin‐2‐yl)­boronic acid derivative

The crystal structure of the first reported non‐substituted N‐methyl­diox­aza­borocane confirms that the presence of a methyl group attached to the N atom introduces an NB bond length that is longer than that in a simple diox­aza­borocane ring. The presence of more N atoms in the vicinity of the B atom in the title compound [systematic name: 6a‐(6‐bromo­pyridin‐2‐yl)‐3a‐methyl‐2,3,4,5‐tetra­hydro‐1,6‐dioxa‐3a‐aza‐6a‐borapentalene], C₁₀H₁₄BBrN₂O₂, does not modify significantly any structural parameter in the diox­aza­borocane ring. On the other hand, a small asymmetry appears in the bond angles of the pyridine C atom next to the B atom.     

A comparison of the ring conformational properties of two derivatives prepared from the same diene ­diacetate precursor

Results of single‐crystal X‐ray experiments performed for the title compounds, (1S,2R,3S,4R,5R)‐4‐benzyl­oxy‐2‐[1‐(benzyl­oxy)­allyl]‐5‐hydroxy­methyl‐2,3,4,5‐tetra­hydro­furan‐3‐ol, C₂₂H₂₆O₅, (I), and (3R,5S,6S,7S,8S)‐3,6‐bis­(benzyl­oxy)‐5‐iodo­methyl‐2,3,4,5‐tetra­hydro­furo­[3,2‐b]­furan‐2‐one, C₂₁H₂₁IO₅, (II), demonstrate that the tetra­hydro­furan ring that is common to both structures adopts a different conformation in each mol­ecule. Structural analyses of (I) and (II), which were prepared from the same precursor, indicate that their different conformations are caused by hydrogen‐bonding interactions in the case of (I) and the presence of a fused bicyclic ring system in the case of (II). Density functional theory calculations on simplified analogs of (I) and (II) are also presented.     

[Hydroxy(aryl)methylene]diphos­phonic acids,a class of drugs in bone pathology treatments,crystallize as head‐to‐head dimers

Two [hydroxy­(aryl)­methyl­ene]­di­phospho­nic acids have been crystallized as dimers. The first compound, [hydroxy­(phenyl)­methyl­ene]­di­phospho­nic acid monohydrate, C₇H₁₀O₇P₂·H₂O, crystallizes in the non‐centrosymmetric space group P2₁, with the two enantiomers related by a non‐crystallographic centre of inversion, while the second compound, [hydroxy(4‐nitro­phenyl)­methyl­ene]­di­phospho­nic acid tetra­hydro­furan disolvate, C₇H₉NO₉P₂·2C₄H₈O, crystallizes in the centrosymmetric space group P2₁/c and uses the centre of symmetry to form the same dimer.     

The new polynuclear titanium(IV) complex [(Cp*TiCl)(μ‐O)2(Cp*Ti)2(μ‐O)(μ‐O)2]2Ti (Cp* is η5‐C5Me5)

A new polynuclear titanium(IV) complex, dichloro­deca‐μ₂‐oxo‐hexa­kis­(penta­methyl­cyclo­penta­dien­yl)hexa­titanium(IV), [Ti₆(C₁₀H₁₅)₆Cl₂O₁₀], has been synthesized by hydro­lysis of a titanium complex bearing an N‐(2‐hydr­oxy‐3,5‐dimethyl­benz­yl)diethano­lamine Mannich ligand. The mol­ecule has two O‐bridged Ti₃O₃ rings linked to two similar rings through a tetra­hedrally O‐coordinated Ti atom. All Ti atoms except the central one are coordinated to penta­methyl­cyclo­penta­dien­yl (Cp*) ligands. The Cp* ligands are arranged with approximate symmetry with respect to the Ti/O/Cl core.     

(Z)‐2‐Methylbuten‐1‐yl(aryl)iodonium trifluoromethanesulfonates containing electron‐withdrawing groups on the aryl moiety

The crystal structures of [(Z)‐2‐methyl­but‐1‐en‐1‐yl]­[4‐(tri­fluoro­methyl)­phenyl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₂H₁₃F₃I⁺·CF₃O₃S^?, (I), (3,5‐di­chloro­phenyl)­[(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₁H₁₂­Cl₂I⁺·CF₃O₃S^?, (II), and bis{[3,5‐bis­(tri­fluoro­methyl)­phenyl][(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium} bis­(tri­fluoro­methane­sulfonate) di­chloro­methane solvate, 2C₁₃H₁₂F₆I⁺·­2CF₃­O₃S^?·CH₂Cl₂, (III), are described. Neither simple acyclic β,β‐di­alkyl‐substituted alkenyl­(aryl)­idonium salts nor a series containing electron‐deficient aryl rings have been described prior to this work. Compounds (I)–(III) were found to have distorted square‐planar geometries, with each I atom interacting with two tri­fluoro­methane­sulfonate counter‐ions.